Mini poll: what temperature sensor are you using?
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@jacotheron said in Mini poll: what temperature sensor are you using?:
- Thermocouples: they are special solid core wires (2 different alloys, specified by the Type, most commonly used is the K-Type) that are fused together at a single point - this is the sensing point. When exposed to different temperatures, it creates a voltage (K-types have a 0.1V/*C graph). The thermocouple wires can't be soldered, as this would create additional sensing points, they can be crimped to different wires. Since the voltage it creates is extremely small, you need an amplifier close by to read it and provide a more useful signal to the controller. Since it is solid core, that part of the sensor may not flex or it will break off. Since it creates a voltage, polarity is very important. Generally for temperatures up to about 290C.
This is probably the range that you may expect for 3D printing, but I have a couple of type K thermocouples measuring temperatures in my exhaust manifold and turbocharger, where I see temperatures in excess of 750 deg C (I get a bit worried when the turbocharger gets close to 800 deg C.) so the thermocouple itself is good to something over 1200 deg C. What may not be able to handle it would be the wire insulation.
Additional note, what thermocouples measure is a temperature gradient. To be truely accurate, the sensing end should be immersed in an ice bath, but since that's not generally possible, most thermocouple readers have a mechanism to check the temperature at the sensing end, which it uses as part of the amplifier circuit to give an adjusted reading.
For my response, I'm using regular thermistors in my printer for the time being. I'd like to upgrade to PT1000 sensors, but as stated, they're difficult to find. For the time being, the thermistor is accurate enough for the temperatures that I'm using, I generally subtract 5 degrees from the manufacturer recommended temperature for filament that I buy, and that seems to be about right.
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I have found a place where I can order PT1000 Class A in 3mm x 15mm cases, MOQ 10pcs, $4.5 for each. But I don't need so many... )
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I used to use 4 wire PT100s but the ones I bought had very fine leads which kept breaking so I changed to simple thermistors. I always do a temperature test print for any new filaments and use whatever temperature is best on my machine. So if my test indicates that the best temperature is (say) 205 deg C, that's what I use for that filament. I don't really care what the true temperature as measured by a more accurate would be.
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@deckingman And this said temperature is stable until thermistor will die, right?
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4 wire PT100
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@phaedrux Class and size please?
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@briskspirit said in Mini poll: what temperature sensor are you using?:
@deckingman And this said temperature is stable until thermistor will die, right?
Seems to be. I've been using the same thermistors for about 18 months and don't have any wildly different temperature results from my test prints. For me, most reels of PLA print best at 195 degC on my machine. That's the values that my test prints showed to be best 18 months ago and I'm still getting the same values now.
I have no idea when the thermistor is likely to die, but then I have no idea when a PT100 or thermocouple would die either. At least when it does die, it'll be cheap to replace.
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@deckingman Hm, good point
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ive just used the standard semitiec thermistor with the e3d for the last 2 years with no problem. Although i just bought a PT1000 from DJdemons site (https://www.precisionpiezo.co.uk/product-page/pt1000-sensor) that fits the standard E3d cartridge so im keen to print some higher temp filaments
